Magnetic random access memory (MRAM) devices are emerging as possible replacements for conventional RAM memory structures such as dynamic and static RAM structures. MRAM devices exhibit similar access speeds and greater immunity to radiation compared to conventional DRAM and SRAM structures, and advantageously do not require applied power to retain their logical state.
FIG. 1 illustrates a block diagram of a conventional MRAM cell structure. The MRAM cell structure generally includes a so-called free layer 102, a reference layer 104, and a barrier junction 106 there between. The free layer 102 and the reference layer 104 are formed from materials that possess a particular magnetic orientation, the relative orientations of which are either parallel, in which case the MRAM cell has a relatively low tunnel magneto resistance between top and bottom electrodes 110a and 110b, or anti-parallel, in which case the MRAM cell has a relatively high tunnel magneto resistance between top and bottom electrodes 110a and 110b. 
The free layer 102 will typically consist of a material that has a lower magnetic coercivity, and can, therefore, more easily be re-oriented, compared to the reference layer 104, which is supposed to keep its magnetic polarization. Reading the state of the MRAM cell is performed by passing a predefined current between the top and bottom electrodes 110a and 110b, and monitoring the resulting voltage. Programming can be performed using one of two conventional techniques. One programming technique is to apply a bit line electrode field current and a word line electrode field current along a particular direction via a top electrode and a bottom electrode to a particular MRAM memory cell located at the top electrode and bottom electrode intersection, the current applied at a sufficient magnitude to generate a magnetic field that aligns the magnetic orientation of the free layer accordingly. However, this approach requires the generation of high current drive levels, resulting in high power dissipation levels and the requirement of large gate periphery transistors to handle the peak current conditions.
Thermally-assisted programming represents another MRAM programming technique known in the art. In this approach, a heating current is supplied across the MRAM's barrier layer, the resistance of which causes the free layer to heat to a predefined temperature. The free layer is preferably constructed from a material that exhibits a decreasing magnetic coercivity with increasing temperature, such that when the free layer is sufficiently heated, lower magnitude field currents can be used to re-orient an existing magnetic polarization of the free layer.
Although thermally-assisted programming contributes to a reduction of a space per bit ratio, there are still requests for a further reduction of the space per bit ratio.